Coolant Flow Channel Arrangement for a Fluid Cooled Electric Motor

Abstract

An improved fluid cooling arrangement for an electric machine, such as an electric motor, a generator, or a motor/generator assembly, is provided. In its most general sense, the fluid-cooled electric machine includes a rotor disposed on a motor shaft, a stator surrounding the rotor, and a motor housing surrounding the stator, with the stator formed of a laminated stack of stator plates that is plated at its outer surface.

1 . A fluid-cooled electric machine comprising:
 a rotor disposed on a motor shaft,   a stator surrounding the rotor, and   a motor housing surrounding the stator,   wherein the stator is formed of a laminated stack of stator plates that is plated at its outer surface, and   wherein a coolant flow passage is defined between the plated outer surface of the laminated stack of stator plates and the motor housing.   
     
     
         2 . The fluid-cooled electric machine as recited in  claim 1 , wherein the coolant flow passage is one of a plurality of coolant flow passages arranged on an outer circumference of the stator, the coolant flow passages being arranged to require a coolant flowing there the coolant flow passages to traverse at least one-half of the circumference of the stator and to reverse flow direction at least once between a coolant entry point of the stator and a coolant exit point of the stator. 
     
     
         3 . The fluid-cooled electric machine as recited in  claim 2 , wherein
 the stack of stator plates includes at least two stator plates having a feature on an outer circumference thereof which, when assembled into the stator, defines at least a portion of a coolant flow channel.   
     
     
         4 . The fluid-cooled electric machine as recited in  claim 3 , wherein
 the outer circumference feature is at least one of a portion of a wall of the coolant flow channel and a portion of a coolant flow crossing point through which coolant passes between adjacent coolant flow channels.   
     
     
         5 . The fluid-cooled electric machine as recited in  claim 4 , wherein
 the coolant flow channel wall includes an opening between adjacent coolant flow channels which is located on the outer circumference of the stator such that coolant passing through the opening into a second of the adjacent coolant flow channels reverses flow direction from a flow direction in the first of the adjacent coolant flow channels.   
     
     
         6 . The fluid-cooled electric machine as recited in  claim 5 , wherein
 the plurality of coolant flow channels are aligned in a circumferential direction around the outer circumference of the stator.   
     
     
         7 . The fluid-cooled electric machine as recited in  claim 6 , wherein
 the opening between adjacent coolant flow channels is arranged such that coolant flowing between adjacent coolant flow channels flows in an axial direction as the coolant passes between the adjacent coolant flow channels.   
     
     
         8 . The fluid-cooled electric machine as recited in  claim 5 , wherein
 the plurality of coolant flow channels are aligned in an axial direction around the outer circumference of the stator.   
     
     
         9 . The fluid-cooled electric machine as recited in  claim 8 , wherein
 the opening between adjacent coolant flow channels is arranged such that coolant flowing between adjacent coolant flow channels flows in a circumferential direction around the outer circumference of the stator as the coolant passes between the adjacent coolant flow channels.   
     
     
         10 . The fluid-cooled electric machine as recited in  claim 9 , wherein
 the opening between adjacent coolant flow channels is located on a stator bell end section arranged on each end of the assembled plurality of stator plates.   
     
     
         11 . The fluid-cooled electric machine as recited in  claim 1 , wherein
 the plated outer surface operates to seal the stack of stator plates against coolant migration into interior regions of the stator.   
     
     
         12 . A stator that is to form a part of a fluid-cooled electric machine including a rotor surrounded by the stator and disposed on a motor shaft, and a motor housing surrounding the stator, the stator comprising:
 a laminated stack of stator plates, and   plating at an outer surface of the laminated stack,   wherein, when the stator is received within the motor housing, a coolant flow passage is defined between the plated outer surface of the laminated stack of stator plates and the motor housing.